The invention concerns a method of monitoring wind power installations, wherein in particular acoustic monitoring is effected.
For effective use of wind power installations, it is advantageous for regulation and operational management of a wind power installation to be carried out in such a way as to ensure fully automatic operation of the installation. Any other mode of operation which requires manual intervention in the normal operating procedure is unacceptable for economic considerations. In order to further increase the economy of the installation, regulation should be effected in such a way that the degree of energy conversion achieved in each operating condition is as high as possible. A further important aspect in terms of regulation and operational management of a wind power installation is operational safety. Technical faults and environmentally induced danger conditions must be recognised and the safety systems present triggered. In addition a regulating system can contribute to reducing the mechanical loading on the wind power installation.
In terms of monitoring wind power installations it is also desirable if remote analysis can be carried out. That has the advantage that detection of respective operating data can be implemented centrally. Remote monitoring of that kind can lead to an increase in the economy of the installation and an increase in the average availability of the installation. In that situation for example the operating data are interrogated and analysed by a service centre or a remote monitoring centre. By means of analysis of the inputted parameters, it is possible on the one hand to afford early recognition of problems occurring, while on the other hand the operating data can provide important indications regarding the production and wind data for the development department. Analysis of such data by the development department can result in improvements to the wind power installation.
In a known wind power installation for example the following parameters are regularly monitored by sensor means: wind speed, wind direction, air density, rotary speed per minute (average and extreme values), temperatures, currents, voltages, switching pulse, lightning strikes (event counters) etc.
Analysis of the inputted parameters by the remote monitoring centre can result in an improvement in the on-site service as the remote monitoring centre can give the on-site service precise indications in regard to the fault sources.
For further improving maintenance, safety and economy of a wind power installation, it is desirable for further parameters of the wind power installation to be monitored.
Therefore, the object of the invention is to improve monitoring of wind power installations.
In accordance with the invention, that object is attained by acoustic monitoring, in addition to the above-described monitoring of a wind power installation.
The advantages achieved with the invention are in particular that it is possible to implement improved early fault detection in order to avoid consequential damage. That for example can result in the recognition of loose screw connections, electrical faults in the generator area, in regard to the inverter, or in regard to the transformer and wear or icing on the rotor blades at an early stage.
In accordance with the invention, for acoustic monitoring of wind power installations, firstly a reference noise spectrum of an installation or parts thereof is recorded and stored. The operating noise spectrum can be continuously or repetitively recorded during operation and compared to the stored reference spectrum and deviations between those two spectra can be detected. Instead of recording a reference noise spectrum of a wind power installation, it is also possible to have recourse to an already stored reference noise spectrum of a wind power installation.
In accordance with an advantageous embodiment of the invention the detected deviations between the operating and reference noise spectra are communicated to a remote monitoring centre in order to undergo central analysis.
Advantageously likewise the original noises which are recorded by a sound pick-up and which have given rise to the deviation between the operating spectrum and the reference spectrum can be communicated to the remote monitoring centre so that the operating personnel at the centre can themselves check the noises by listening thereto.
In that respect it is particularly advantageous to form a noise pattern from the original noises and in turn to build up an acoustic data bank from those noise patterns.
If the deviations between the operating spectrum and the reference spectrum are greater than a predetermined threshold value the wind power installation is possibly switched off.